Water storage tank

Folks, it is getting dry in South Texas (West Travis County) I am on a well in the Trinity. Wells around me are going dry. I have decided to at least install a pump shut off switch to save my pump motor. However, I am also interested in a storage tank. We are 60 years old and live alone. We occasionally have our children and grand children in, but just for the day. I do irrigate my lawn and shrubs. About 10,000 sg ft of lawn. What size is recommended? Some have suggested 2500 gal. of black plastic. I am totally in the dark about this. Thanks.

If you believe you can get by with only 25 gallons per day, 2500 gallons would last for around three months ... but I suspect "black plastic" would get plenty warm or even hot during the daytime and cause a lot of evaporation.

Maybe some other folks here have some real-life experience with cisterns and can tell you what will work best.